1. Field of the Invention
The invention is directed to an electric thin-film circuit and a method for its production, including the steps of applying various thin films, forming the circuit, and selectively etching the components from these thin films.
2. Prior Art
The U.S. Pat. application Ser. No. 408,100 of Oct. 19, 1973 explains in detail that tantalum-aluminum alloys are well suited for electric thin-film circuits disposed upon a substrate made of an insulator material, and that particularly favorable electric values are obtained in view of temperature coefficients and the time constancy, when the tantalum content is relatively low, compared with the aluminum content, for instance in the range between 2 and 20 atomic percent.
It was stressed in this application that the aluminum forms a so-called face-centered cubic lattice (fcc lattice), in the case of a tantalum content of approximately 7 atomic percent or less, instead of forming a tetragonal lattice as this is the case with a higher tantalum content. The fcc lattice entails a great time stability of the finished electric components which were produced in accordance with this tantalum-aluminum thin-film technique.
The present invention proceeds from this suggestion and provides a method permitting the construction of a thin-film circuit in the tantalum-aluminum technique, comprising a capacitor and at least one conductor path and or at least one resistor, whereby the tantalum-aluminum oxide layer forming the capacitor dielectric is produced as independently as possible from the conductor path or the resistor path, in order to minimize production tolerances.